Fire alarm system



June 10, 1941. c. L. HILL EEAL FIRE ALARM SYSTEM I Filed July 1, 1939INVENTORS BY I 4 ATTORNEYS.

WITNESS.

Patented June 10, 1941 UKTED EYTATES ATENT EFilii FIRE ALARM SYSTEMCharles L. Hill, Cranford, and Lawrence Fahn, North Plainfield, N. J.

5 Claims.

This invention relates to improvements in fire alarm systems and hasparticular reference to an electric circuit closer therefor.

The primary object of the invention resides in an electric circuitcloser or switch for fire alarm systems in which the increased airpressure caused by heat in pipe-line circuits serves to actuate the samefor closing an electric alarm circuit to audibly and/or visually givewarning of a fire which may occur on the property protected by the alarmsystem.

Another feature of the invention is to provide an electric circuitcloser which is readily responsive to an unusual rise in temperature onthe premises protected by the system in which the circuit closer isarranged, but which is non-responsive to natural atmospherictemperatures so as not to sound false fire alarms.

A still further feature of the invention is the provision of arrelectric circuit responsive to unusual temperature rises which functionson an overbalancing principle and which includes a novel means ofpreventing the accidental overbalancing of the circuit closer when thesystem is installed on ships which may be caused by the tossing of aship during stormy weather which otherwise would cause a false operationof the circuit closer device.

A still further feature of the invention is to provide a fire alarmsystem which is simple and inexpensive of construction, easy ofinstallation, and exceptionally sensitive to a sudden rise intemperature upon the property protected by the fire alarm system.

Other features of the invention will be apparent as the followingspecification is read in conjunction with the accompanying drawing, inwhich:

Figure 1 is a front elevational View of our improved fire alarm systemwith parts broken away in section.

Figure 2 is a vertical transverse sectional View approximately on theline 2-2 of Figure l including the electrical alarm circuit.

Figure 3 is an enlarged detail vertical sectional view through one ofthe air relief vents and the air inlet leading thereto.

Referring to the drawing by reference characters, the numeral l0designates an air pressure electric circuit closer which includes a flatbase I I having an inverted U-shaped frame !2 fixed thereto and risingupwardly therefrom. The frame 12 comprises a pair of spaced verticalparallel rails I3I3 and a top bridge rail Hi.

Tapped into opposite ends of the bridge rail M are ducts l5-i5, theinner ends of each of which opens into an enlarged recess 16 which opensonto the top and bottom, of the top bridge rail through reduced roundholes I l. The outer portion of each duct is screw threaded andthreadedly receives a tube l3 forming part of a pipe coupling it betweenthe bore l5 and one end of an air pressure detector tube or pipe line2a. The detector tube or pipe line 28 is constructed of flexiblematerial to permit the installation of the same about a room or premisesintended to be protected by the fire alarm; system and by reference toFigure l of the drawing, it will be seen that the pipe line 29 iscontinuous and the ends thereof are respectively connected to the ductsI5-l5 by means of the couplings l9l9. Extending through. each pair ofvertically alined holes l'l-l'! and recess i6 is a bolt 2i having athreaded shank 22 which extends beyond the top of the bridge rail l4,and a head 23, there being a sealing washer 24 interposed between thehead 23 and the underside of the bridge rail. A relatively small bore 25extends axially through the bolt 2| and radial openings 26 establishcommunication between the bore 25 and the recess H5. A nozzle 2'5 havingan internally screw threaded nipple 23 is threaded to the projecting endof the bolt 2! and a seal- .ing washer 29 is interposed between thenipple 23 and the top surface of the bridge rail M. The upper end of thenozzle 2T terminates in a tapered portion and fitting into the bore 35!of the nozzle at the tapered end is a relatively small diameter steelrustproof tube 3|. An inverted cone shaped housing member 32 is threadedto the nozzle 2! and the upper portion thereof is disposed in spacedrelation to the tube 3! and is provided with air outlet holes 33 in theside walls thereof.

From the description thus far, it will be understood that the ends ofthe detector tube 2B communicate with the atmosphere through air reliefnozzles 39, but by means of restricted passages defined by the smalldiameter tubes 3!.

Mounted in horizontally alined bearing screws 34-44 which are mounted inthe vertical rails l3l3 and bridging the space therebetween, is a rod35. Fixedly mounted on the rod 35 in substantially vertical alinementwith the bolts 21-2! are a pair of normally balanced electric switchactuating members 36-36 and in view of the fact that they are identicalin construc tion and attachment to the rod 35, a description of one willsufiice for the other.

Each switch actuating member 36 includes a light weight U-shaped glasstube 3'! having a short leg portion 38 opening to the atmosphere throughthe outwardly flared open end 39, and a long leg portion G whichterminates in an inwardly offset reduced tapered end ll normallydisposed in vertical alinement with the rod and a bolt 2!. The glasstube 31 is connected to the rod 35 by fixed clamping plates d2 i2 andthe clamping plates are in turn loosely mounted on the rod 35 forturning movement but are held against sliding movement by collars t3fixed to the rod whereby the U-shaped glass tubes 3! are pivotallymounted on the rod for independent rocking movement relative to eachother. I

The tapered ends 4! of the two actuating members 36-36 are respectivelyconnected to the bores 25 of the bolts 2| by relatively small diameterflexible tubes A l. The tubes it are coiled to provide sufficient slackto enable free swinging movement of the members 36.

Each U-shaped glass tube 31 contains a quantity of liquid substancewhich is relatively light in weight and of a quality which is relativelyslow in evaporation under atmospheric conditions. The liquid substance55 fills the bight portion of the glass tube and rises in columns intothe leg portions 38 and 48 thereof to a level approximately one half thelength of the leg portion 38.

Mounted on the base H and insulated therefrom is a support in the formof a wall 46, the same rising from the base and being disposed adjacentthe leg portions 40 of the glass tubes 3?. Insulated from the support itare a pair of spring contact members 41-41, the same being respectivelydisposed in the path of outward swinging movement of the leg portionstil of the glass tubes 31. The spring contact members 41 are normallydisposed in spaced relation to fixed adjustable contact screws 48threaded in the support 45. The support at is of conducting material andthe same is connected to a ground it forming part of an electric alarmcircuit 53 in which the spring contacts ll-41 are arranged in parallelwith a battery or other source of electric energy 5|, one pole of whichis grounded asat 52. Also arranged in the alarm circuit 50 is an audibleelectric bell 53 and a manually actuated master switch 54. Ininstallation wherein a plurality of individual fire detector pipes 20and switch actuating devices 36 are arranged, the same may beoperatively connected by electric circuits similar to the circuit 55) toan annunciator 55 for visually indicating the particular stationdetector units as they respond to excessive temperature rises in thecon-- fined areas protected by this improved fire alarm system.

In practice, the balanced switch actuating members 3636 of a detectorunit assume the normal position shown in full lines in Figure 2 of thedrawing, wherein the same are disposed in spaced relation with respectto the spring contact members ll-d1. The pipe or tube 20 contains airand any gradual rise in temperature which may cause expansion of the airtherein is exhausted to the atmosphere through the restricted airdischargetubes 3!. Should the tube 2% be subjected to a sudden rise oftemperature such as would occur by reason of a fire in the vicinitythereof, the expansion of the air within the tube would create anincreased air pressure therein which would not be exhausted to theatmosphere through the restricted discharge tubes 3|, and this excessair pressure finds its way to the restricted tubes 54 and into the longlegs 46 of one of the switch actuating members 36. Should the fire becloser to one end of the tube than the other, that switch actuatingmember 36 at that end will function first. The air pressure entering aleg Ml forces the liquid substance, 45 therein into the shorter leg 38causing an overbalancing of this actuating member whereupon the leg ii)forcibly strikes its related spring contact member 41 and forces it intocontacting engagement with its related contact screw it, thereuponclosing the circuit 50 and setting off the audible alarm device 53 andindicating the set off station detector unit on the annunciator 55. Thecircuit closing position of the actuating member 36 is illustrated indotted lines in Figure 2 of the drawing. In use, the switch actuatingunit iii may be enclosed in a casing to prevent the accumulation of dustand dirt thereon and also prevent undue evaporation of the liquidsubstance 45. Should the liquid substance 45 drop below a predeterminedlevel, the same may be replaced by a fresh supply poured into the legportion 38 through the open flared end 33.

When the fire alarm system is installed on ships, it is possible thatthe roll of a ship may cause a false alarm due to the tilting of theactuating members 36 in the direction of the spring contacts ll. Toprevent such an occurrence, we have provided an automatic stop forarresting accidental movement of the members 35. the side rails I3 is aninverted L-shaped counter balance lever 51 which carries a balanceweight 53 at its lower end. The short leg 59 of the inverted L-shapedlever 51 is provided with a stop arm til which extends through theU-shaped glass tubes 31 and is normally disposed adjacent the short legs38 but clear of the limit of the normal actuating movement so as not tointerfere with the movement of the actuating members to circuit closingposition when the unit I 0 is in a vertical position. However, shouldthe unit be tilted in a direction which would cause the spring contactsd! to move toward the legs all of the members 36, such movement will beprevented by the arm 68 which is disposed in the path of movement of thelegs 38 by reason of the counterbalance weight 58.

While we have shown and described what we consider to be the preferredembodiment of our invention, we wish it to be understood that suchchanges in construction and design as come within the scope of theappended claims may be resorted to if desired.

Having thus described the invention, what we claim as new and desire tosecure by Letters Patent of the United States, is:

1. A circuit closer device comprising a support, a horizontal rodfixedly mounted in said support, a holder member rockably mounted onsaidshaft, a substantially U-shaped tube member having leg portions and abight portion, means connecting the leg portions to said holderequidistant from the axis of turning movement of said holder member, aninwardly offset tubular extension formed integral with one leg portionof said U- shaped tube member, said tubular extension terminating in arestricted air pressure inlet, a length of relatively small diameterflexible tubing having one of its ends fitted into the inlet while theother end of said tubing is adapted to be connected to an air pressureline, and a liquid substance partially filling said U-shaped Pivoted at56 to the inner side of one of tube member and serving to assist innormally holding the same in balance whereby air pressure in excess ofatmospheric pressure which may be introduced into said tube memberthrough the inlet end thereof will cause the shifting of the liquidsubstance from the inlet leg portion to the other leg portion of theU-shaped tube member to eiTect an overbalancing of the tube member tocause the lower portion of the inlet leg portion to swing outwardly inan operating direction, and an electric push switch arranged in the pathof outward operative swinging movement of the said inlet leg portion foractuating the same.

2. A circuit closer device comprising in combination a base, a pair ofspaced opposed rigid uprights rising upwardly from said base, a rodhaving its ends respectively mounted in said uprights, a cross armrockably mounted on said rod, a substantially U-shaped tube memberhaving spaced leg portions and a connecting bight portion, meansconnecting the leg portions to said cross arm equidistantly from theaxis of said rod, a restricted air inlet provided in the free end of oneleg portion while the free end of the other leg portion opens to theatmosphere, a liquid substance partially filling the U-shaped tubemember and extending into the leg portions thereof to assist in normallyholding the U- shaped tube member in suspended balance whereby airpressure in excess of atmospheric air pressure when introduced into theU-shaped tube member through the inlet end thereof will cause theshifting of the liquid substance from that leg portion having the airinlet to the other leg portion to effect an overbalancing of the U-shaped tube member to cause the lower portion of the leg portion havingthe air inlet to swing outwardly in an operating direction, a bracketmounted on said base, a fixed electric contact mounted on said bracket,and a spring contact mounted on said bracket and normally out ofengagement with the fixed contact, said spring contact being disposed inthe path of outward operative swinging movement of the U-shaped tubemember to be strikingly engaged thereby for movement into engagementwith said fixed contact.

3. A circuit closer device as set forth in claim 2, including a pendulummember pivotally mounted on one of the uprights, and a stop arm on saidpendulum member disposed in the path of the U-shaped tube member forarresting accidental swinging movement of the same in an operatingdirection when the device is acciden tally tilted in such direction.

4. A circuit closing device comprising a support, a substantiallyU-shaped tube member pivotally mounted intermediate its top and bottomin pendulum fashion on said support for swinging movement, said U-shapedmember having a short leg portion having its end opening to theatmosphere, a long leg portion having an air pressure inlet at its end,and a bight portion connecting the'leg portions; 3, liquid substancecontained within said tube member and rising into the legs at a commonlevel, a normally open electric push spring switch mounted on saidsupport to one side of the U-shaped tube member and disposed in the pathof outward swinging movement of the long leg portion whereby airpressure in excess of atmospheric air pressure which may enter the longleg portion through the pressure inlet will cause the level of theliquid substance in the short leg portion to rise and that in the longleg portion to drop to effect an overbalancing of the tube member tocause the long leg portion thereof to strikingly engage the push switch,and a counterbalance stop member mounted on the support and disposed inthe path of switch closing swinging movement of the tube member toprevent accidental actuation of the push switch upon accidental tiltingof the support.

5. A circuit closer device comprising a support, a substantiallyU-shaped tube member having an air pressure inlet at one end, the otherend of said member opening to the atmosphere, means for pivotallymounting said tube member intermediate its top and bottom in pendulumfashion upon said support, a liquid substance contained in said tubemember and only partially filling the same, said tube member beingnormally in a balanced perpendicular position, whereby air in excess ofatmospheric air which may be introduced into said tube member throughthe inlet end thereof will effect a shifting of the liquid substancefrom one side of the pivotal axis of the U-shaped tube member to theother side thereof to effect an overbalance of said tube member to causethe lower end thereof to swing outwardly in an operating direction, apush switch element disposed in the path of outward swinging operatingmovement of said tube member for actuation thereby, and a stop means inthe path of outward swinging operating movement of the U-shaped tubemember for arresting the swinging movement of the tube member in anoperating direction when the support is tilted to prevent accidentalactuation of the push switch element.

CHARLES L, HILL. LAWRENCE FAHN.

